crazy - Popularized in the post millenium as a substitute for cool, hip, exciting, dope, off the hook and was widely accepted by middle class whites.
2. An adjective describing an individual (particularly a gangsta) who is mentally unstable and prone to bursts of violence or recklessness without regard to oneself.

1. "Me and my nigga saw Kill Bill yesterday. That shit was crazy."
2. "...and he just cut that fool for swiping his corn starch. Man, that nigga's crazy."

'Crazy' is generally a positive, desirable characteristic (unless you are very calm yourself), describing someone who is very out there, fun to be with, unrestricted, creative and plain awesome. You might associate a crazy person with partying, being ridiculously obscene and loud in public with their friends, and cracking jokes. You would not usually find a crazy person pondering on their philosophy of life, discussing how amazing War Literature is or talking about how delightfully tasty their English tea is.

Crazy people can either be cool or just plain annoying. There is the crazy that everyone loves, where you are the life of the party, or the crazy that goes overboard, where people want to avoid you.

1) "Hey, did you see Mia at the party last night?"

"Yeah, oh my God, she was on the tables dancing half naked, kissing girls, everything. That girl is crazy, I love it!"

2) "Did you see that new girl in school?"

"I heard about her, she set off 3 fire alarms on her first day thinking that everyone would find it hilarious, but it was sooo childish and dumb! that girl is too fucking crazy."